Structure of photovoltaic cell

ABSTRACT

A structure of photovoltaic cell is provided. The structure of photovoltaic cell includes a substrate, a lower conductive layer, a photovoltaic layer, and an upper conductive layer, the lower conductive layer is disposed at one side of the substrate, the photovoltaic layer is disposed at the other surface of the lower conductive layer, and the upper conductive layer is disposed on the other surface of the photovoltaic layer. An electron transporting layer, a hole transporting layer, and an active layer sandwiched between the electron transporting layer and the hole transporting layer collectively constitute the photovoltaic layer. The electron transporting layer convers a portion of the active layer and the hole transporting layer for blocking the upper conductive layer from electrically connecting to the active layer and the hole transporting layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 15/832,187, filed on Dec. 5, 2017, and entitled “A STRUCTURE OFPHOTOVOLTAIC CELL”. The entire disclosures of the above application areall incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to a structure of photovoltaic cell. Moreparticularly, the present disclosure relates to an arrangement structureof an electron transporting layer or a hole transporting layer of aphotovoltaic cell.

Description of Related Art

A solar cell is one of the most promising renewable energy sourcesavailable now. Although most of the commercialized products utilize thesilicon as their main material, the solar cells still attract theattention of the industrial and academic fields due to the simplemanufacturing procedure, the low manufacturing cost, the light material,and the flexibility.

While manufacturing the photovoltaic solar cell, a membrane of the solarcell is manufactured by coating or evaporation which render the membraneprovide with a better flatness and uniformity. The R2R manufacturingprocess is a potential technique used for manufacturing photovoltaicsolar cells with a large area, and the R2R manufacturing processcooperates with an operation in the industrial circles can produce thephotovoltaic component with the advantages of plasticity, light weight,and bump-resistance.

As shown in FIG. 1, the structure of photovoltaic cell of photoelectricconversion element, such as organic photovoltaic cell or Perovskitesolar cell, provides photoelectric conversion mechanism by thephotovoltaic layer 103 a disposed on the substrate 101 a and constitutesa circuit loop through an upper conductive layer 104 a and lowerconductive layer 102 a. The photovoltaic layer 103 a is constituted byan electron transporting layer 1031 a, an active layer 1032 a, and ahole transporting layer 1033 a, and the effects of photoelectricconversion and electron transportation are achieved by combining thephotovoltaic layer 103 a with the upper conductive layer 104 a and thelower conductive layer 102 a. The active layer 1032 a may be selectedfrom organic photovoltaic (OPV) materials or Perovskite (PSC)photovoltaic materials. The electron transporting layer 1031 a and thehole transporting layer 1033 a with different electric characteristicscan further enhance the photoelectric conversion efficiency of theactive layer 1032 a.

The R2R manufacturing procedures processes a high productivitymanufacture of the structure of photovoltaic cell; however, theprobability of a short circuit in the area between the photovoltaiclayer 103 a and the upper conductive layer 104 a increases due to thelateral side of the photovoltaic layer 103 a is partially electricallyconnected to the upper conductive layer 104 a. Even through thethickness of lateral sides of each layer in the photovoltaic layer 103 ais smaller than 1 μm, the probability of the short circuit in the areabetween the photovoltaic layer 103 a and the upper conductive layer 104a increases due to the lateral sides of the active layer 1032 a and theelectron transporting layer 1031 a are contacted with the upperconductive layer 104 a. Therefore, the present disclosure intends toprovide a structure of photovoltaic cell capable of eliminatingshort-circuit between the photovoltaic layer 103 a and the upperconductive layer 104 a for enhancing the photoelectric conversionefficiency and meeting the high productivity manufacture of thestructure of photovoltaic cell.

SUMMARY

According to one aspect of the present disclosure, the presentdisclosure discloses a structure of photovoltaic cell, which isadvantageous for forming the photovoltaic cell by a continuousroll-to-roll manufacturing process and solving the short-circuit problemdue to contact between a lateral side of a photovoltaic layer and anupper conductive layer of the photovoltaic cell.

According to one aspect of the present disclosure, a structure ofphotovoltaic cell includes at least one hollowed hole formed on theupper conductive layer of each cell to make sure that the cells arelight-transmittable.

In view of the above, the structure of photovoltaic cell includes asubstrate, a lower conductive layer, a photovoltaic layer, and an upperconductive layer. The lower conductive layer is disposed on one side ofthe substrate, the photovoltaic layer is disposed at the other surfaceof the lower conductive layer, the upper conductive layer is disposed onthe other surface of the photovoltaic layer; wherein the photovoltaiclayer is constituted by an electron transporting layer, a holetransporting layer, and an active layer sandwiched between the electrontransporting layer and the hole transporting layer. The electrontransporting layer convers a portion of the active layer and the holetransporting layer for blocking the upper conductive layer fromelectrically connecting to the active layer and the hole transportinglayer.

In an embodiment of the present disclosure, the substrate is anoptical-transparent plastic substrate or an optical-transparent glasssubstrate.

In an embodiment of the present disclosure, the structure ofphotovoltaic cell further includes a hardening layer disposed betweenthe substrate and the lower conductive layer.

In an embodiment of the present disclosure, a thickness of thephotovoltaic layer is smaller than 1 μm.

In an embodiment of the present disclosure, the photovoltaic layer is astructure of organic photovoltaic cell that uses multi-layers functionaldesign.

In an embodiment of the present disclosure, the photovoltaic layer is astructure of Perovskite photovoltaic cell that uses multi-layersfunctional design.

In an embodiment of the present disclosure, a top cover made oftransparent material is disposed on the structure of photovoltaic celland an encapsulation is placed between the top cover and the substrateso that the top cover is glued to the substrate.

In an embodiment of the present disclosure, a top cover is disposed onthe structure of photovoltaic cell and a bottom cover is disposed belowthe structure of photovoltaic cell, and an encapsulation is placedbetween the top cover and the bottom cover so that the top cover isglued to the bottom cover.

In an embodiment of the present disclosure, the upper conductive layerhas at least one hollowed hole.

BRIEF DESCRIPTION OF DRAWING

The present disclosure can be more fully understood by reading thefollowing detailed description of the embodiment, with reference made tothe accompanying drawings as follows:

FIG. 1 illustrates an example of a structure of photovoltaic cell inaccordance with the related art;

FIG. 2 illustrates a flow chart for fabricating a structure ofphotovoltaic cell in accordance with a 1st embodiment of the presentdisclosure;

FIG. 3 illustrates a side view that fabricates a lower conductive layeron a structure of photovoltaic cell in accordance with the 1stembodiment of the present disclosure;

FIG. 4 illustrates a top view of FIG. 3;

FIG. 5 illustrates a side view that fabricates an electron transportinglayer and an active layer on the lower conductive layer of FIG. 3;

FIG. 6 illustrates a top view of FIG. 5;

FIG. 7 illustrates a side view that fabricates a hole transporting layeron the active layer of FIG. 6;

FIG. 8 illustrates a top view of FIG. 7;

FIG. 9 illustrates a side view that fabricates an upper conductive layeron the hole transporting layer of FIG. 8;

FIG. 10 illustrates a top view of FIG. 9;

FIG. 11 illustrates a schematic diagram of a structure of photovoltaiccell in accordance with a 2nd embodiment of the present disclosure;

FIG. 12 illustrates a schematic diagram of a structure of photovoltaiccell in accordance with a 3rd embodiment of the present disclosure;

FIG. 13 illustrates a schematic diagram of a structure of photovoltaiccell in accordance with a 4th embodiment of the present disclosure.

DETAILED DESCRIPTION

A preferred embodiment of the present invention will be described withreference to the drawings.

FIG. 2 illustrates a flow chart for fabricating a structure ofphotovoltaic cell in accordance with a 1st embodiment of the presentdisclosure, and FIG. 3 illustrates a side view that fabricates a lowerconductive layer on a structure of photovoltaic cell in accordance withthe 1st embodiment of the present disclosure. In FIG. 2 and FIG. 3, thestructure of photovoltaic cell includes a plurality of cells arranged inarray on a substrate 1, each cell includes a lower conductive layer 2, aphotovoltaic layer 3, and am upper conductive layer 4. An electrontransporting layer 31 (or the hole transporting layer 33) of thephotovoltaic layer 3 covers a portion of an active layer 32 and aportion of the hole transporting layer 33 (or the electron transportinglayer 31) thereof for blocking the upper conductive layer 4 fromelectrically connecting to the active layer 32 and the hole transportinglayer 33 (or the electron transporting layer 31).

At first, in step S100, a substrate is provided; the substrate 1 may bean optical-transparent plastic substrate or an optical-transparent glasssubstrate. The optical-transparent plastic substrate is selected fromthe group comprising polyethylene terephthalate (PET), polyethylene(PE), polyimide (PI), nylon, polyamide (PA), polyurethanes (PU), andpolymethylmethacrylate (PMMA). Thereafter, a hardening layer (not shown)is provided on a surface of the substrate 1 by executing a curingtreatment; the (optical) hardening layer may include PMMA, epoxy, andsilicon dioxide, which may be used alone or in combinations thereof. Thethickness of the hardening layer is 1 μm-5 μm.

In step S102, the lower conductive layer is provided; the lowerconductive layer 2 is disposed on a side surface of the hardening layer.The organic or inorganic conductive coating is dry-etched (such as laseretched), wet-etched (such as chemical etched), or evaporated to form aplurality of transparent electrons 21 and circuit(s) (not shown) of thelower conductive layer 2, and the lower conductive layer 2 is disposedon the side surface of the hardening layer. The lower conductive layer 2may include organic conductive coating and inorganic conductive coating,which may be used alone or in combinations thereof; the organicconductive coating may be metal or metallic oxide, and the inorganicconductive coating may be carbon nanotube, andpoly-3,4-ethylenedioxythiophene (PEDOT), which may be used alone or incombinations thereof. As shown in FIG. 3 and FIG. 4, the width of eachfirst etching trench 2 a formed between two adjacent electrodes 21 is 25μm-100 μm.

In step S104, the photovoltaic layer 2 is provided; the photovoltaiclayer 2 is formed on each electrode 21 of the lower conductive layer 3by slot die coating, evaporation, or screen printing. More particularly,each electrode 21 of the lower conductive layer 2 is sequentially coatedwith the electron transporting layer 31 and the active layer 32 (or eachelectrode 21 of the lower conductive layer 2 may be sequentially coatedwith the hole transporting layer 33 and the active layer 32) which arethen dried and etched (as shown in FIG. 5 and FIG. 6). The width of eachsecond etching trench 3 a formed between two adjacent cells 3 is 50μm-100 μm. A coating step is then provided for forming the holetransporting layer 33 (or the electron transporting layer 31) to shieldthe lateral sides of the electron transporting layer 31 and the activelayer 32 (or shield the lateral sides of the hole transporting layer 33and the active layer 32), so as to block the electron transporting layer31 and the active layer 32 (or block the hole transporting layer and theactive layer 32) from electrically connecting to the upper conductivelayer (not shown) for sequent processing. The hole transporting layer 33(or the electron transporting layer 31) may be formed by slot diecoating, evaporation, or screen printing, and is then dried and etched.The width of each third etching trench 3 b formed between two adjacenthole transporting layer 33 (or the electron transporting layer 31) ofeach cell 3 is 25 μm-100 μm (as shown in FIG. 7 and FIG. 8). thephotovoltaic layer 3 is a structure of organic photovoltaic cell thatuses multi-layers functional design or a structure of Perovskitephotovoltaic cell that uses multi-layers functional design. In thisembodiment, the thickness of the photovoltaic layer 3 is smaller than 1μm.

In step S106, the upper conductive layer 4 is provided. The conductivecoating, such as silver paste, is coated with the hole transportinglayer 33 (or the electron transporting layer 31) of each photovoltaiclayer 3 and convers the lower conductive layer 2 of the nextphotovoltaic layer 3, such that the upper conductive layer 3 iselectrically connected to the lower conductive layer 2 (as shown in FIG.9 and FIG. 10). It should be noted that the conductive wire for externalconnection may be formed when fabricating the upper conductive layer 4.

Reference is made to FIG. 11, which illustrates a schematic diagram of astructure of photovoltaic cell in accordance with a 2nd embodiment ofthe present disclosure. The structure of photovoltaic cell in the 2ndembodiment is similar to the 1st embodiment mentioned above. Thedifference is that the structure of photovoltaic cell in this embodimentfurther includes at least one hollowed hole 41 formed on the upperconductive layer 4 of each cell to make sure that the cells arelight-transmittable.

Reference is made to FIG. 12, which illustrates a schematic diagram of astructure of photovoltaic cell in accordance with a 3rd embodiment ofthe present disclosure. The structure of photovoltaic cell in the 3rdembodiment is similar to the 1st embodiment mentioned above. Thedifference is that the structure of photovoltaic cell in this embodimentfurther includes a top cover 20 made of transparent material. Anencapsulation 40 is placed between the top cover 20 and the substrate 1for offering good water and gas barrier capability. The transparentmaterial may be an optical-transparent glass plate or anoptical-transparent plastic plate.

Reference is made to FIG. 13, which illustrates a schematic diagram of astructure of photovoltaic cell in accordance with a 4th embodiment ofthe present disclosure. The structure of photovoltaic cell in the 4thembodiment is similar to the 1st embodiment mentioned above. Thedifference is that the structure of photovoltaic cell in this embodimentfurther includes a top cover 20 and a bottom cover 30 made oftransparent material. An encapsulation 40 is placed between the topcover 20 and the bottom cover 30 for offering good water and gas barriercapability. The transparent material may be an optical-transparent glassplate or an optical-transparent plastic plate.

Although the present disclosure has been described with reference to theforegoing preferred embodiment, it will be understood that thedisclosure is not limited to the details thereof. Various equivalentvariations and modifications can still occur to those skilled in thisart in view of the teachings of the present disclosure. Thus, all suchvariations and equivalent modifications are also embraced within thescope of the disclosure as defined in the appended claims.

What is claimed is:
 1. A structure of photovoltaic cell, comprising: asubstrate; a lower conductive layer disposed on one side of thesubstrate; a photovoltaic layer disposed at a side surface of the lowerconductive layer; and an upper conductive layer disposed on the otherside surface of the photovoltaic layer; wherein the photovoltaic layeris constituted by an electron transporting layer, a hole transportinglayer, and an active layer sandwiched between the electron transportinglayer and the hole transporting layer, and wherein the electrontransporting layer convers a portion of the active layer and the holetransporting layer for blocking the upper conductive layer fromelectrically connecting to the active layer and the hole transportinglayer.
 2. The structure of photovoltaic cell of claim 1, wherein thesubstrate is an optical-transparent plastic substrate or anoptical-transparent glass substrate.
 3. The structure of photovoltaiccell of claim 1, further comprising a hardening layer disposed betweenthe substrate and the lower conductive layer.
 4. The structure ofphotovoltaic cell of claim 1, wherein a thickness of the photovoltaiclayer is smaller than 1 μm.
 5. The structure of photovoltaic cell ofclaim 1, wherein the photovoltaic layer is a structure of Perovskitephotovoltaic cell that uses multi-layers functional design.
 6. Thestructure of photovoltaic cell of claim 1, wherein a top cover isdisposed on the structure of photovoltaic cell and a bottom cover isdisposed below the structure of photovoltaic cell, and an encapsulationis placed between the top cover and the bottom cover so that the topcover is glued to the bottom cover.
 7. The structure of photovoltaiccell of claim 1, wherein the upper conductive layer has at least onehollowed hole.